The invention generally relates to a fluidizer for a substance for gassing, preferably aerating, a liquid or fluidizing a particulate substance, such as a powder. Such fluidizers may include a material having microscopic holes to permit the escape of a gas for fluidizing, or may include a non-cylindrical shape and include a body at least partially positioned within a flow of a particulate substance.
Generally, the invention also relates to techniques and apparatuses for consistently and uniformly transporting and delivering particulate substances such as powders. Such transport and delivery systems can be used for filling cavities such as in die-casting machines prior to powder compaction in processes for fabricating consolidated parts for automotive, aerospace, micro-electronics, vitamins, pharmaceuticals, and the like. Particulates such as powders are typically fed from a main hopper and transferred through a tube to a feed or fill shoe which deposits the particulates into a die cavity by gravity or pressure.
However, prior art fluidizers suffer several disadvantages. One disadvantage is that these fluidizers are made from inflexible materials. As a result, they are not readily transformable into suitable shapes for a desired application. Consequently, if a fluidizer is desirable for a particular application, it must be carefully designed so as to be in the proper shape for installation. There is no ability to adjust the fluidizer should it not be suitably designed for the application, or if it is desired to modify the fluidizer for another application or to another device.
Another disadvantage typically associated with fluidizers is that they have more than one inlet connection for receiving a fluid, such as a gas, for fluidizing a substance. As a result, multiple inlet connections provide more opportunities for leaks to develop and these fluidizers may have greater maintenance costs.
In addition, there are several problems associated with prior art processes for powder delivery and filling of die cavities especially die cavities for high-precision, small parts. One such problem is a variation or inconsistency in powder flow in the tube connecting a main hopper or powder supply to a feed shoe on a die surface of a die casting machine. Clumping and surging of the particulates within the tubing and/or the feed shoe also contribute to the non-uniform filling of die cavities. Mechanical shaking of the feed structure above the die cavity can reduce clumping in the powder and improve fill uniformity, but such shaking is not necessarily consistent during successive filling operations. Moreover, such shaking causes segregation of fine materials from coarse materials which results in a loss of uniformity in particle-size distribution and chemical composition.